Japan nuclear expert: Massive “re-melting” occurred at Reactor No. 3 (DIAGRAM)

Published: August 8th, 2011 at 10:33 am ET
By
Email Article Email Article
9 comments


Japanese Researcher Says Reactor 3′s Fuel Melted Twice, Dropped to Containment Vessel, EX-SKF, August 8, 2011:

From Asahi Shinbun (3:02AM JST 8/8/2011; not the literal translation)

[Fumiya Tanabe, former head of the research at Japan Atomic Energy Agency] thinks the fuel melted and dropped to the bottom of the Reactor Pressure Vessel of Reactor 3 by March 14′s explosion; then the melted fuel stayed there, cooled by more than 300-tonnes/day water. However, the amount of water injected dropped to only 24 tonnes per day from March 21 to 23, and 69 tonnes per day on March 24, probably due to increased pressure within the RPV.

It caused the melted fuel to heat up again, and the fuel melted through the RPV and dropped onto the Containment Vessel (pedestal; see the diagram from Asahi).

According to Tanabe, the amount of water from March 21 to 24 was only about 11 to 32% of what was needed to remove the decay heat, and within one day the melted fuel would attain the melting temperature again.

Tanabe thinks this massive “re-melting” caused the release of a large amount of radioactive materials into the environment which caused a spike in air radiation in wide areas of Tohoku and Kanto including Tokyo, and most of the re-melted fuel dropped from the RPV to the Containment Vessel.

Tanabe will present the result of his research on Reactor 3 at Fukushima I Nuclear Power Plant in the upcoming Atomic Energy Society of Japan’s conference next month.

See also: “Most” of the fuel at Reactor No. 3 may have breached vessel after melting down again

Published: August 8th, 2011 at 10:33 am ET
By
Email Article Email Article
9 comments

Related Posts

  1. Japan nuke expert: I presume melted fuel reacted violently with cement at Reactor No. 3, releasing large amounts of radioactive materials outside — TEPCO responds August 9, 2011
  2. “Most” of the fuel at Reactor No. 3 may have breached vessel after melting down twice August 8, 2011
  3. Kyodo: “Unit 3 MOX likely melted through” — Mixed uranium-plutonium oxide fuel may have “dribbled” out after melting again August 9, 2011
  4. L.A. Times: Speculation that “supercritical fission event” occurred at Fukushima reactor irradiating plutonium, says nuclear expert — Explosion so massive investigators found fuel rod fragments a mile away March 9, 2012
  5. NHK: “This is a very severe accident” — Nuclear fuel at Reactor No. 1 may have melted through 65 cm of concrete… Only 37 cm at thinnest point (PHOTOS) November 30, 2011

9 comments to Japan nuclear expert: Massive “re-melting” occurred at Reactor No. 3 (DIAGRAM)

  • pg

    I thought this happened months ago…you know, after it exploded and sent pieces of fuel rod in a two mile radius.

    Something else is going on like Daini or Oganawa is coming unglued.

    stay sharp


    Report comment

    • VanneV anne

      Here is the whole article with a chart of the second spike of radiation on Mar 21:
      Japanese Researcher Says Reactor 3′s Fuel Melted Twice, Dropped to Containment Vessel
      From Asahi Shinbun (3:02AM JST 8/8/2011; not the literal translation):
      Fumiya Tanabe, former head of the research at Japan Atomic Energy Agency, will present the result of his research on Reactor 3 at Fukushima I Nuclear Power Plant in the upcoming Atomic Energy Society of Japan’s conference next month.

      http://www.asahi.com/national/update/0807/images/TKY201108070413.jpg
      Tanabe thinks the fuel melted and dropped to the bottom of the Reactor Pressure Vessel of Reactor 3 by March 14′s explosion; then the melted fuel stayed there, cooled by more than 300- tonnes/day water. However, the amount of water injected dropped to only 24 tonnes per day from March 21 to 23, and 69 tonnes per day on March 24, probably due to increased pressure within the RPV.
      It caused the melted fuel to heat up again, and the fuel melted through the RPV and dropped onto the Containment Vessel (pedestal; see the diagram from Asahi).

      According to Tanabe, the amount of water from March 21 to 24 was only about 11 to 32% of what was needed to remove the decay heat, and within one day the melted fuel would attain the melting temperature again.

      Tanabe thinks this massive “re-melting” caused the release of a large amount of radioactive materials into the environment which caused a spike in air radiation in wide areas of Tohoku and Kanto including Tokyo, and most of the re-melted fuel dropped from the RPV to the Containment Vessel.
      The article doesn’t say what Tanabe thinks has happened to the melted fuel that dropped onto the Containment Vessel since.
      But the article does say this:
      TEPCO hopes to have a “cold shutdown” where the temperature at the bottom of the RPV is low [below 100 degrees Celsius] as the target for winding down the nuclear accident. But if the fuel core is mostly melted and has dropped down to the Containment Vessel, it may affect the “roadmap”.
      No kidding. Yes it may. Where have you been, Asahi, for all these months? Is this news to you?
      Tanabe’s chart (from Asahi article) plotting the air radiation level (in microsieverts/hour) shows a spike on March 21. It rained that day in Tokyo.
      http://www.asahi.com/national/update/0807/images/TKY201108070411.jpg

      http://ex-skf.blogspot.com/2011/08/japanese-researcher-says-reactor-3s.html


      Report comment

  • Pallas89juno Pallas89juno@yahoo.com

    This is another minimization piece, as fare as I can tell. I wouldn’t be surprised if the R3 corium is, in fact already under the containment building. I’m not expert; but I can’t see how water is going to have much effect on a corium blob, particularly if the containment beneath the prssure vessel is concave, lensing the blob into a shape which would prevent the interior of the mass from being cooled properly and it’s already high in plutonium, even boronated water isn’t going to do much except delay inevitable re-criticalities eventually leading here to more explosions until the fuel is divided enough to actually be able to be cooled or to slow down runaway chain reactions by being divided into small enough sections of corium.


    Report comment

  • odylan

    Ah, good old number 3 again. The devastating plutonium mox nuclear explosion if my memory is corrected. It happened so long ago.


    Report comment

  • odylan

    Is this by any chance the “radioactive pancake” ?

    Info is available from a tried and tested source – and we don’t have to wait until “next month”.

    http://www.fairewinds.com/content/lethal-levels-radiation-fukushima-what-are-implications


    Report comment

  • theypoisonus

    I admit it, I am indeed a pessimist but in this case, I have been overly hopeful alot of the time, or tried to untill I got po’ed.

    There is an echo … that is all this is.

    We aren’t even ‘experts’ and we know this already. Thanks to Arnie and all the articles we have read and sleuthed out collectively.

    At least someone in Japan is saying it, so maybe the Japanese People will add 1 = 1, finally. I sure hope so for their sakes.


    Report comment

  • Heart of the Rose Heart of the Rose

    …now…SEE..the scientific consensus that we have struggled to maintain is correct….
    There is no joy in being correct….


    Report comment

  • Misitu

    Satisfaction, perhaps, relief, and self confidence.

    And a skill honed for future use.


    Report comment